1. Technical Field of the Invention
The present invention relates to a component mounting apparatus for mounting parts such as electronic components onto a substrate or the like. More particularly, the invention relates to a component mounting apparatus having a rotary mounting section provided with a plurality of mounting heads on the outer periphery thereof.
2. Description of Related Art
A known high-speed component mounting apparatus includes a rotary mounting section 1 for picking up components from a given component supply source 3 in a supply section 2 and for placing the components on a substrate 5 positioned on an X-Y table 4, as shown in FIG. 6. The apparatus further has a transfer rail for carrying in and out the substrate 5, and a display unit for indicating operating conditions and alarms, should the apparatus malfunctions.
The rotary mounting section 1 includes, as shown in FIG. 7, a rotary table 8 having a plurality of mounting heads 10 on its outer periphery, only one of which is shown in the drawing for ease of illustration, and a rotary drive member 9 having a rotary shaft 8a at its lower face for imparting intermittent motion of the rotary table 8 at a pitch space corresponding to the distance between two adjacent mounting heads 10. Each of the mounting heads 10 includes a suction nozzle 10a for holding a component and a motor 11 used for switching the suction nozzle from one type to another.
The rotary drive member 9 is provided with a support plate 9a thereon which rotates integrally with the rotary shaft 8a. At the peripheral edge of the support plate 9a is provided a plurality of box-shaped drivers 51 for respectively driving each of the motors 11. A mercury contact type connector 52 is provided in the center of the support plate 9a for inputting drive power and control signals for the motors 11 to the drivers 51 from a controller (not shown) built in a stationary part of the apparatus. The drivers 51 output the drive power and control signals thus inputted thereto via the connector 52 to the motors 11 of their respective mounting heads 10 through a wiring 12 passing through the hollow interior of the rotary shaft 8a and the rotary table 8.
Since the circular support plate 9a holds the plurality of evenly spaced box-shaped drivers 51 thereon at its circumference, the space required for allowing the support plate with drivers to freely rotate is reduced as compared to a case where a single such box-shaped driver is held on the support plate. Nevertheless, these drivers 51 still require a relatively large installation space because of their corners protruding beyond the circumference of the support plate, thereby increasing the radius of rotation of the support plate. This causes bulkiness of the apparatus.
The driver 51 accommodates various circuit boards or substrates therein, among which the one having a motor driver for controlling electric current applied to the motor 11 is subjected to a large load and apt to generate heat. It is therefore desirable to cool the substrate, but it is built in a confined space in close proximity to other substrates within a box and effective cooling thereof is hardly achieved. Such substrate is also apt to fail because of the heat, but replacement of the substrate requires considerable work and time in view of the built-in structure, causing the productivity to lower.